Cyan color formers



United States Patent Ofiice 3,079,259 Patented Feb. 26, 1963 3,079,259 CYAN (101L011 FURMERS Emil B. Ranch, Port Dickinson, and Charles R. Hance, Endweli, N.Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed July 21, 196i), ar. No. 44,268 2 Claims. (Cl. 96-180) are composed of the subtractive primary colors, i.e., cyan,

magenta and yellow. In the multi-layer color systems in use today, magenta dye images are usually produced from pyrazolone structures; the yellow dye images are derived from reactive ketomethylene compounds, whereas the cyan images are produced from phenolic substances such as phenols or naphthols. Photographic dye images as above described are formed in situ with the silver images which are subsequently removed or otherwise bleached to leave the pure dye images.

One of the major difiiculties confronting color photography is to provide dyes possessing proper spectral photographic properties. Thus, in a colored photograhic reproduction employing the subtractive color process three subtractively colored dye images are placed in overlapping registration. The function of the subtractively dyed images, which are yellow, magenta and cyan respectively, is to modulate white light. Expressed in another manner each of the three subtractively superimposed images absorbs the required amount of white light. When the three dyed images are viewed in white light and in perfect register, a colored reproduction representing the colored aspects of the original subject is thereby produced.

Ideally, each of the three subtractively colored layers should absorb one-third of the visible light spectrum, i.e., the yellow image should absorb blue, the magenta should absorb green and the cyan layer should absorb in the red portion of the spectrum. However, in actual practice this latter condition is approached but never achieved. Consequently, the search for color couplers capable of yielding on color development a truer subtractively dyed image continues.

As previously pointed out, cyan dye images are commonly derived from naphthol color formers. Structures which have shown promise in this connection are the anilides of 1-hydroxy-2-naphthoic acid containing an alkoxyl group in the ortho position of the anilide portion of the molecule and being further provided with carboxy or sulfo solubilizing functions. The latter are preferably located ortho or para to the alkoxy group. The compounds disclosed in the prior art although yielding dye images possessing desirably high stability under conditions of excessive humidity proved to be too green when used in a reversal color material. On investigation, it was found that the excessive greenish hue was not so much due to the absorption in the red sensitive region of the spectrum, as to the rather excessive blue absorption of the dyes produced from these couplers. It was realized that an excellent naphthol cyan color coupler might be evolved if it were possible to design a chemical structure having all the stability towards excessive humidity of the prior art structures, but modified in such a manner as to eliminate the undesirable absorption in the blue region of the spectrum.

It is, therefore, the principal object of this invention to provide a cyan naphthol color former having a low absorption in the blue portion of the spectrum.

A further object is to provide naphthol coupler compounds which produce cyan dyes having a high degree of heat and light stability.

A still further object is to provide naphthol coupler compounds which produce cyan dyes having a high degree of resistance under conditions of high humidity.

Other objects will appear hereafter as the description proceeds.

The aforesaid objects are accomplished according to our invention by providing cyan coupler compounds formulistically depicted below:

tic; .51.

wherein X is a mildly electropositive neutral substituent such as lower alky1,i.e., methyl, ethyl, butyl, etc., halogen, e.g., chlorine, bromine, etc. and lower alkoxyl, methoxyl, ethoxy propoxyl, butoxyl, etc. and R is an alkyl group of from 10 to 20 carbon atoms, e.g., decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonodecyl, etc.

Specific compounds forming Within the ambit of the above formula include the following structures:

I O 012E (3) 0 H CH3 0 H I H CN-- S Cali (4) OH OLHII I S 0 3H H H i -N GQHE:

( o I. p

CIHHN -N Br OaH the invention.

Preparation of Compound 3 l hydroxy methyl-2'-tetradecoxy-4-sulfo-2-naphthanilide was prepared as follows: 4.9, g. of 2-tetradecoxy- 5-methyl-1-hydroxy-2-naphthanilide was dissolved in 25 cc. of dry carbon tetrachloride to which 1 cc. of chlorosulfonic acid was addedat room-[temperature with stirring. Stirring was continued forone hour at room temperature and for three hours t nder reflux. The mixture was allowed to cool to 20-C. and 1 g. of sodium chloride in cc. of water was added with stirring. All the volatile material was removed under reduced pressure and the residue of the sodium salt of the coupler was crystallized from acetonitrile. Yield: 3.6 g. (60%) M.P. 104-105 C.

Analysis.Calc.E N, 2.37; S, 5.41. Found: N, 2.50; S, 5.40. Y

1 hydroxy 5 -.methyl-2'-tetradecoxy-Lnaphthanilide was prepared as follows: 11.1 g. of {3-amino-4-tetradecoxytoluene and 10.3 g. of phenyl-l-hydroxy-Z-naphthoate was heated together to 140 C. and held there for two hours. The hot melt was poured into an evaporating dish and triturated with methanol. The solid was filtered 0E and crystallized from isopropanol. The yield of purified material was 9.2 g. (54%) M.P. 58-59 .C.

Analysis-Cale; N, 2.85. Found: N, 3.01.

3-amino-4-tetradecoxytoluene waslprepared as follows: 32 g. of 3-acetamino-4-tetradecoxytoluene and 150 cc. of acetic acid and 115 cc. of concentrated HCl were refluxed for three hours. After cooling to room temperature the solution was poured into an excess of cold water. The amine hydrochloride which separated was filtered 01f, washed with water and sucked dry. The solid was redispersed in water and 40 cc. of concentrated NH OH was then added. After heatingya short time on the steam bath the fi'ee base separated as an oil which, on cooling, solidified. It was filtered 01f, washed .with water and crystallized from methanol. Yield: 2-3 g. (-81%) M.P. 4344 C.

Analysis.--Calc.: N, 4.39. Found: N, 4.45.

3-acetamino-4-tetradecoxytoluene was prepared as follows: 23. g. of 3-acetamino-p-cresol, and 30, g. oftetradecylbromide' and 7.5 .g. of sodiummethoxidein 375 cc. of absolute alcohol was refluxedfor six hours. fIhe mixture wasallowed to stand at room temperatureovernight and then poured into an excess of water. The solid which separated was filtered, washed with Water and crystallized frommethanol. The yield of purified ,product was 2 9.8 g. (6.0%,) M.P. 62-.63 C.

' AnalisisJ-Calc; C, 76.40;.1-1, 10.86; N,.3.87. Found: C, 7 6.00, 75.62; H, 10.88, 10.57; N, "4.16,,4-26.

' The ,ahoveed'etailed synthesisof Compound ,3 is generally applicable to thecoupler compounds asvdesc'ribed herein. 4 For instance, Compound 5 can be prepared .by reactingYl-hydroxyQ-naphthoic acid phenyl ester with daethyl 2-tridecoxy aniline followed by sulfonationwith chlorosulfonic acid. Compound .7 can be produced by condensing l-hydroxy-Z-naphthoic acid phenyl ester 4-ethyl-2-deG XY aniline followed by .sulfonation with chlorosulfonic acid. The remaining coupler compounds formulistical-ly depicted elsewhere canbe produced in like manner by condensing the appropriate long chain alkoxy aniline with the phenyl .ester of -1 hydroxy-2-naphthoic acid. Thearequisiteflo rtho long .chain alkoxy aniline can be obtained .by methods known in the organic chemical art, and'thefdetailed preparation ofthese entities is not deemednecessary, Isince such .l;now l.edge wetness obvious tofaskil led organictechnician. i i

:It is to besnoted that the salt forming ,sulfo group .is attached to the'4or coupling positionof the .color iformers. However, the indoam'line dye images produced on color development .do -not .contain the sulfosuhstituent sincedtis eliminated. in the color forming reaction. Thus, whereas th,e' color formers aresolublejn aqueous alkali or solutionsthereofithe dyes themselves have no solubilizing group and are therefore of .a .lipophilic nature. This isa valuahleproperty since it tends Ito-make the dyes resistant to ,-f ading under conditions of excessive humidity.

Our colonformers may -be incorporatedin silver halide emulsions inthe manner known .to the var-t. Thus, the couplers are dissolved in an aqueous alkaline solution and are their combined with the silver halide emulsion, which is then coated .on .a suitable support or base.

Although it is a common practice to incorporate .onr color formers in gelatin layers, other photographic .col-

loids may also be employed for this purpose. Thus,

synthetic res'insisuch as polyvinyl alcohol, carhoxymethyl cellulose, starch, gum arabic, casein, zein, etc. can be used as carriers. I i

The primaryaromatic amino developing agents of the type used .to produce colored photographic images color couplers are known to the photographic field.

Suitable developing agents include the various alltyl phenylenediamines such as 4-am inoaniline, 4 -ethylarhinoaniline, Z- diethylaminoaniIine, 4-dialkylaminoaniline, e.g., 4-dimethylaminoaniline, 4-diethylaminoaniline, 4.[N-.(B- hydroxyethyl) N-ethyl] aminoaniline, 4-amino-N-ethyl-N- B-methanesulfonamidoethyl) 2-methylalniline sulfate and the like. The above developing agents are preferably used in the form of their salts such asthe hydrochloride or .hydrosnltate as they .are more soluble and stable than thefree bases. All of these compoundshave a primary amino group which enables' the oxidation product of the developer to couple with the color compounds to form dye images. After removal of the silver image by bleaching and fixing in a manner well known in the art, the color image remains in the emulsion. A typical developing solution can be prepared as follows:

G. 2-amino-S-diethylaminotoluene 2 Sodium carbonate (anhydrous) 20 Sodium sulfite (anhydrous) 2 Potassium bromide 0.2

Water to make 1 liter.

The exposed silver halide emulsions containing the color formers are developed in the above solution in the usual manner.

Bases which are useful for holding the emulsion layers containing our color couplers may be any of the usual supports. For instance, bases such as a cellulose ester, polystyrene, polyamide, polyester or a non-transparent reflecting material such as paper have proved suitable for this purpose.

As pointed out elsewhere, the cyan naphthol color formers produced in accordance with the invention yield on color development cyan dye images having a low absorption in the blue range of the electromagnetic spectrum. As a consequence, the images are not plagued with the undesirable greenish hues characteristic of the dye images of the prior art. This constitutes a decided advantage in reproducing an accurate rendition of the color aspects of a colored subject. In addition to these desirable spectral properties, our color formers display high stability when subjected to excessively high humidity and light intensities.

It is to be understood that the extent of our invention is not limited except as necessitated by the appended claims.

6 We claim: 1. A photographic silver halide emulsion containing as a color forming coupler a compound having the following formula:

SOaH

wherein X is a substituent selected from the class consisting of lower alkyl, halogen and lower alkoxyl and R is an alkyl group of from 10 to 20 carbon atoms.

2. A photographic silver halide emulsion containing as a color forming coupler a compound having the following formula:

649,660 Great Britain Jan. 31, 1951 

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING AS A COLOR FORMING COUPLER A COMPOUND HAVING THE FOLLOWING FORMULA: 